This application relates to a fault reasoning and guided troubleshooting system, which combines aspects of model-based reasoning, and case-based reasoning to provide a hybrid approach.
One method of identifying faulty components in large systems, such as gas turbine engines, is called “fault reasoning”. This is the process of estimating the root cause of a problem in a system based upon a set of faults, or symptoms. As an example, a number of sensors may be placed throughout a system, such as a gas turbine engine, and provide signals to a fault reasoner. The signals could provide indications of potential faults or problems throughout the system. For instance, unusually high or low temperatures, unusually high or low pressures, etc. may be sent to the fault reasoner. The combination of these faults would indicate particular problem(s) within the system. It is the goal of the fault reasoning system to predict what may be failing based upon the combination of faults.
One known fault reasoning system is a so-called model-based reasoner. A model-based reasoner is based upon a model of the system, and provides potential solutions to the combination of faults based upon modeling of the system. Thus, a model-based reasoner might be fully functional and operational even before a new piece of equipment has been deployed.
A case-based reasoner is based on real life experience, and matures as the equipment ages. As equipment ages, it is typical that more and more faults occur, and corresponding repairs must be put in place. Thus, a case-based reasoner is more effective after a piece of equipment has been operational for a period of time than it may have been initially.
The case-based reasoner, once it has built an adequate database, tends to emulate the results predicted by a model-based reasoner. On the other hand, the model-based reasoner is more likely to be able to make a better prediction of a particular root cause(s) based upon a combination of faults than is a case-based reasoner, especially in early stages of operation of a new piece of equipment.